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| United States Patent |
6,194,088
|
|
Yoshida
, et al.
|
February 27, 2001
|
Stainless steel coated with intermetallic compound and process for
producing the same
Abstract
An intermetallic-compound coated stainless steel having excellent rigidity,
toughness, wear resistance and corrosion resistance comprises a substrate
of a martensite stainless steel having a Vickers hardness of 400 or more,
and a hard film having a bottom surface adhered to the substrate and an
exposed top surface. The hard film has an outermost layer made of a
compound selected from the group consisting of a Ti--Ni intermetallic
compound, Ti--Fe intermetallic compound, and a mixture of the Ti--Ni
intermetallic compound and a Ti--Cu intermetallic compound. The coated
stainless steel can be produced by cladding an outer sheet made of Ti or a
Ti alloy to a martensite stainless steel sheet directly or through an
intermediate sheet made of Ni, Fe or a Ni--Cu alloy, heating the laminate
at a temperature of 900.degree. C. to 1150.degree. C. for 30 seconds to 5
minutes, and then cooling the heated laminate at a cooling rate of
1.degree. C./sec or more.
| Inventors:
|
Yoshida; Hiroaki (Tokai, JP);
Yamada; Hiroshi (Kasugai, JP);
Iwane; Fumio (Nagoya, JP);
Imai; Junji (Amagasaki, JP);
Hamada; Tadashi (Sakai, JP);
Fujimoto; Shinji (Hirakata, JP);
Yamada; Shuji (Ashiya, JP);
Sakon; Shigetoshi (Hirakata, JP)
|
| Assignee:
|
Daido Steel Co., Ltd. (Nagoya, JP);
Matsushita Electric Works, Ltd. (Osaka, JP)
|
| Appl. No.:
|
331589 |
| Filed:
|
July 1, 1999 |
| PCT Filed:
|
November 11, 1998
|
| PCT NO:
|
PCT/JP98/05082
|
| 371 Date:
|
July 1, 1999
|
| 102(e) Date:
|
July 1, 1999
|
| PCT PUB.NO.:
|
WO99/24633 |
| PCT PUB. Date:
|
May 20, 1999 |
Foreign Application Priority Data
| Current U.S. Class: |
428/660; 148/530; 428/679; 428/685; 428/941 |
| Intern'l Class: |
B32B 015/18; C22F 001/18; C22C 010/28 |
| Field of Search: |
428/685,660,679,677,682,683,941
148/530,532,534,537
|
References Cited
U.S. Patent Documents
| 2786265 | Mar., 1957 | Keay, Jr. | 428/660.
|
| 3015885 | Jan., 1962 | McEuen et al. | 428/660.
|
| 3071491 | Jan., 1963 | Horn et al. | 428/660.
|
| 3125805 | Mar., 1964 | Horigan, Jr. | 428/660.
|
| 3615902 | Oct., 1971 | Lesney | 148/12.
|
| 4485149 | Nov., 1984 | Sprenger et al. | 428/627.
|
| 4612259 | Sep., 1986 | Ueda | 428/661.
|
| 4839242 | Jun., 1989 | Murayama et al. | 428/660.
|
| 5190831 | Mar., 1993 | Banker | 428/660.
|
| Foreign Patent Documents |
| 62-203687 | Sep., 1987 | JP.
| |
| 63-318985 | Dec., 1988 | JP.
| |
| 1-35918 | Jul., 1989 | JP.
| |
| 1-309791 | Dec., 1989 | JP.
| |
| 3-115559 | May., 1991 | JP.
| |
| 10-29104 | Feb., 1998 | JP.
| |
Primary Examiner: Zimmerman; John J.
Attorney, Agent or Firm: Arent Fox Kintner Plotkin & Kahn, PLLC
Claims
What is claimed is:
1. An intermetallic-compound coated stainless steel comprising:
a substrate of a martensite stainless steel, said substrate having a
Vickers hardness of 400 or more; and
a hard film having a bottom surface adhered to said substrate and an
exposed top surface, said hard film having an outermost layer made of a
compound selected from the group consisting of a Ti--Ni intermetallic
compound, Ti--Fe intermetallic compound, and a mixture of said Ti--Ni
intermetallic compound and a Ti--Cu intermetallic compound.
2. The coated stainless steel as set forth in claim 1, wherein said hard
film has a TiFe.sub.2 layer, and a TiFe layer formed on said TiFe.sub.2
layer as said outermost layer.
3. The coated stainless steel as set forth in claim 2, wherein said hard
film has a TiC layer formed under said TiFe.sub.2 layer.
4. The coated stainless steel as set forth in claim 1, wherein said hard
film has a TiNi.sub.3 layer, and a TiNi layer formed on said TiNi.sub.3
layer as said outermost layer.
5. The coated stainless steel as set forth in claim 1, wherein said hard
film has a mixture layer of TiNi and TiCu as said outermost layer.
6. The coated stainless steel as set forth in claim 1, wherein said
martensite stainless steel contains 12 to 20 wt % of Cr, 0.3 to 0.8 wt %
of C, and 2.5 wt % or less of Mo.
7. A method of producing an intermetallic-compound coated stainless steel
comprising the steps of:
preparing a laminate by cladding an outer sheet made of one of Ti and a Ti
alloy to a martensite stainless steel sheet through an intermediate sheet
made of one of Ni, Fe and a Ni--Cu alloy; and
performing a quench hardening treatment to said laminate to harden said
stainless steel to a Vickers hardness of 400 or more, and form a hard film
including an outermost layer made of an intermetallic compound between Ti
of said outer sheet and a metal element of said intermediate sheet on said
stainless steel sheet, said quench hardening treatment comprising the
steps of heating said laminate at a temperature of 900.degree. C. to
1150.degree. C. for 30 seconds to 5 minutes, and then cooling said
laminate at a cooling rate of 1.degree. C./sec or more.
8. The method as set forth in claim 7, wherein a thickness of said outer
sheet in said laminate is within a range of 1 to 10 .mu.m and a thickness
of said intermediate sheet in said laminate is 1 to 3 times of that of
said outer sheet.
9. A method of producing an intermetallic-compound coated stainless steel
comprising the steps of:
preparing a laminate by cladding an outer sheet made of one of Ti and a Ti
alloy directly to a martensite stainless steel sheet;
performing a quench hardening treatment to said laminate to harden said
stainless steel to a Vickers hardness of 400 or more, and form a hard film
having a TiC layer, a TiFe.sub.2 layer formed on said TiC layer, and a
TiFe layer formed on said TiFe.sub.2 layer as an outermost layer, on said
stainless steel sheet, said quench hardening treatment comprising the
steps of heating said laminate at a temperature of 900.degree. C. to
1150.degree. C. for 30 seconds to 5 minutes, and then cooling said
laminate at a cooling rate of 1.degree. C./sec or more.
10. The method as set forth in claim 7 or 9, wherein an annealing treatment
characterized in that said laminate is heated and kept at a temperature of
700.degree. C. to 800.degree. C. for 15 seconds to 2 minutes is performed
to said laminate prior to said quench hardening treatment.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an intermetallic-compound coated stainless
steel, which can be used for parts requiring excellent rigidity,
toughness, wear resistance and corrosion resistance, for example,
structural parts such as gears and bearings, and cutting tools such as
hair clippers and blades for electric shavers, and a method of producing
the same.
2. Disclosure of the Prior Art
In the past, carbon tool steels, high carbon stainless steels, or
precipitation-hardening stainless steels have been used to structural
parts such as gears and bearings, and cutting tools such as hair clippers
and blades for electric shavers. Although these materials are excellent in
toughness, the wear resistance is not enough. To improve the wear
resistance, conventional ceramics can be used. However, they have not been
practical yet in applications requiring complex configuration or sharp
edge because of poor toughness and workability of the ceramics. On the
other hand, a surface modification of the foregoing steels can be
performed by coating a hard material having excellent corrosion resistance
such as alumina by means of physical vapor deposition (PVD) method or
chemical vapor deposition (CVD). In this case, since a thickness of the
coated hard material is very thin, for example, 0.1 .mu.m, sufficient wear
resistance has not been obtained yet. In addition, there is a problem that
the adhesion between the coated hard material and the steels is not
enough.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an intermetallic-compound
coated stainless steel having excellent rigidity, toughness, wear
resistance and corrosion resistance. That is, the coated stainless steel
comprises a substrate of a martensite stainless steel, and a hard film
having a bottom surface adhered to the substrate and an exposed top
surface. The stainless steel of the substrate has a Vickers hardness of
400 or more. The hard film has an outermost layer made of a compound
selected from the group consisting of a Ti--Ni intermetallic compound,
Ti--Fe intermetallic compound, and a mixture of the Ti--Ni intermetallic
compound and a Ti--Cu intermetallic compound.
When the outermost layer is made of the Ti--Fe intermetallic compound, it
is preferred that the hard film has a TiFe.sub.2 layer, and a TiFe layer
formed on the TiFe.sub.2 layer as the outermost layer.
When the outermost layer is made of the Ti--Ni intermetallic compound, it
is preferred that the hard film has a TiNi.sub.3 layer, and a TiNi layer
formed on the TiNi.sub.3 layer as the outermost layer.
When the outermost layer is made of the mixture of the Ti--Ni intermetallic
compound and the Ti--Cu intermetallic compound, it is preferred that the
hard film has a mixture layer of TiNi and TiCu as the outermost layer.
A further object of the present invention is to provide a method of
producing the intermetallic-compound coated stainless steel. That is, a
laminate is prepared by cladding an outer sheet of Ti or a Ti alloy
directly on a surface of the martensite stainless steel, or cladding the
outer sheet on the martensite stainless steel through an intermediate
sheet of Ni, Fe or a Ni--Cu alloy. Then, a quench hardening treatment is
performed to the laminate. That is, the laminate is heated and kept at a
temperature of 900.degree. C. to 1150.degree. C. for 30 seconds to 5
minutes, and then cooled at a cooling rate of 1.degree. C./sec or more. By
the quench hardening treatment, the stainless steel is hardened to a
Vickers hardness of 400 or more, and at the same time the hard film is
formed on the hardened stainless steel. When the laminate is prepared by
cladding the outer sheet on the stainless steel sheet through the
intermediate sheet, the hard film having the outermost layer made of an
intermetallic compound between Ti of the outer sheet and the metal element
of the intermediate sheet is formed on the stainless steel by the
foregoing hardening treatment. On the other hand, when the laminate is
prepared by cladding the outer sheet directly on the stainless steel
sheet, the hard film having a TiC layer, a TiFe.sub.2 layer formed on the
TiC layer, and a TiFe layer formed on the TiFe.sub.2 layer as the
outermost layer, is formed on the stainless steel by the foregoing
hardening treatment.
When using the intermediate sheet, it is preferred that a thickness of the
outer sheet in the laminate is within a range of 1 to 10 .mu.m and a
thickness of the intermediate sheet in the laminate is 1 to 3 times of the
thickness of the outer sheet.
In the above method, when the laminate is worked by a plastic deformation
prior to the foregoing hardening treatment, it is preferred to perform the
working after an annealing treatment in which the laminate is heated and
kept at a temperature of 700.degree. C. to 800.degree. C. for 15 seconds
to 2 minutes.
These and still other objects and advantages will become apparent from the
following detail description of the preferred embodiments and examples of
the invention referring to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing changes of Ti, Ni, Cr and Fe concentrations
measured in the depth direction from a laminate surface before a quench
hardening treatment of Example 1;
FIG. 2 is a diagram showing changes of Ti, Ni, Cr and Fe concentrations
measured in the depth direction from a hard film surface after the quench
hardening treatment of Example 1;
FIG. 3 is a diagram showing a hardness change measured in the depth
direction from a surface of an intermetallic-compound coated stainless
steel of Example 1;
FIG. 4 is a SEM photograph of a cross section of an intermetallic-compound
coated stainless steel of Example 22;
FIG. 5 is a SEM photograph of an interface portion between a hard film and
a stainless steel substrate of Example 22;
FIG. 6 is a photograph showing a distribution of Fe at the interface
portion of FIG. 5;
FIG. 7 is a photograph showing a distribution of Cr at the interface
portion of FIG. 5;
FIG. 8 is a photograph showing a distribution of Ti at the interface
portion of FIG. 5; and
FIG. 9 is a photograph showing a distribution of C at the interface portion
of FIG. 5.
DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENTS
An intermetallic-compound coated stainless steel of the present invention
comprises a substrate of a martensite stainless steel as a substrate, and
a hard film having a bottom surface adhered to the substrate and an
exposed top surface. The stainless steel of the substrate has a Vickers
hardness of 400 or more. When the Vickers hardness is less than 400, the
coated stainless steel of the present invention is not sufficient in
hardness, strength and rigidity to use for structural parts such as gears
and bearings, and cutting tools such as hair clippers and blades for
electric shavers. In the present invention, it is preferred to use the
martensite stainless steel having a composition of 12 to 20 wt % of Cr,
0.3 to 0.8 wt % of C, 2.5 wt % or less of Mo, and the balance of Fe. To
achieve a quench hardening of the stainless steel by a thermal treatment
explained later, it is required that the carbon content is 0.3 wt % or
more. In addition, if necessary, required amounts of Si, Mn, V, and/or Nb
may be added to the above composition.
The hard film has an outermost layer made of a compound selected from the
group consisting of a Ti--Ni intermetallic compound, Ti--Fe intermetallic
compound, and a mixture of the Ti--Ni intermetallic compound and a Ti--Cu
intermetallic compound.
In case of the Ti--Ni intermetallic compound, it is preferred that the hard
film has a TiNi.sub.3 layer, and a TiNi layer formed on the TiNi.sub.3
layer as the outermost layer. It is preferred that a total thickness of
the TiNi.sub.3 layer and TiNi layer is within a range of 1 to 15 .mu.m. In
case of using the intermetallic-compound coated stainless steel of the
present invention for blades of an electric shaver, when the total
thickness is less than 1 .mu.m, an improvement of the wear resistance is
small. On the other hand, when the total thickness is more than 15 .mu.m,
there is a possibility of causing chippings at the blades. Therefore, when
the total thickness of the TiNi.sub.3 layer and TiNi layer is within the
above range, it is possible to provide excellent shaving performance over
an extended time period while preventing the occurrence of the chippings.
In case of the Ti--Fe intermetallic compound, it is preferred that the hard
film has a TiFe.sub.2 layer, and a TiFe layer formed on the TiFe.sub.2
layer as the outermost layer. From the same reason described above, it is
preferred that a total thickness of the TiFe.sub.2 layer and TiFe layer is
within the range of 1 to 15 .mu.m. In addition, under a specific condition
explained later, it is preferred that the hard film has a TiC layer, a
TiFe.sub.2 layer formed on the TiC layer, and a TiFe layer formed on the
TiFe.sub.2 layer as the outermost layer. From the same reason described
above, it is preferred that a total thickness of the Tic layer, TiFe.sub.2
layer and the TiFe layer is within the range of 1 to 15 .mu.m.
In case of the mixture of the Ti--Ni intermetallic compound and the Ti--Cu
intermetallic compound, it is preferred that the hard film has a first
mixture layer of TiNi and TiCu as the outermost layer. A second mixture
layer of TiNi.sub.3, Ti.sub.2 Cu.sub.3, and TiCu.sub.2 may be formed under
the first mixture layer. From the same reason described above, it is
preferred that a total thickness of the first and second mixture layers is
within the range of 1 to 15 .mu.m.
Next, first and second methods of producing the intermetallic-compound
coated stainless steel of the present invention are explained. In the
first method, a laminate is prepared by cladding an outer sheet of Ti or a
Ti alloy on one side or both sides of a martensite stainless steel sheet
through an intermediate sheet of Ni, Fe or a Ni--Cu alloy. As the Ti
alloy, it is preferred to use a Ti--Pd alloy, e.g., Ti- 0.15wt % Pd alloy,
a Ti--Mo--Ni alloy, e.g., Ti- 0.3wt % Mo-0.8wt % Ni alloy, or a Ti--Ta
alloy, e.g., Ti-5wt % Ta alloy. When using the Ni--Cu alloy as the
intermediate sheet, it is preferred that the copper content is within a
range of 10 to 35 wt %.
Then, a quench-hardening treatment is performed to the laminate. That is,
the laminate is heated and kept at a temperature of 900.degree. C. to
1150.degree. C. for 30 seconds to 5 minutes, and then cooled at a cooling
rate of 1.degree. C./sec or more. In particular, it is preferred that the
laminate is heated and kept at 1050.degree. C. for 1 to 2 minutes, and
then cooled at a cooling rate of 50.degree. C./sec. By the
quench-hardening treatment, the stainless steel is hardened to a Vickers
hardness of 400 or more, and at the same time the hard film having the
outermost layer made of the intermetallic compound between Ti of the outer
sheet and Fe or Ni of the intermediate sheet, or the hard film having the
outermost layer made of the mixture of the Ti--Ni intermetallic compound
and the Ti--Cu intermetallic compound, is formed on the stainless steel.
When the treatment time is more than 5 minutes, Ti of the outer sheet
diffuses into the stainless steel through the intermediate sheet, and
reacts with carbon in the stainless steel to generate TiC, so that the
carbon content in the stainless steel decreases. Due to the decrease of
the carbon content, the quench-hardening of the substrate is not
sufficiently achieved. In other words, the stainless steel having the
Vickers hardness of 400 or more can not be obtained as the substrate
supporting the hard film. In addition, when the treatment time is less
than 30 seconds, it is difficult to uniformly perform the quench-hardening
treatment to the laminate. As a result, the quench hardening of the
substrate is not uniform, and the formation of the hard film is
insufficient. When the treatment temperature is more than 1150.degree. C.,
a diffusion rate of Ti increases, so that there causes a problem, which is
the same as the problem occurring when the treatment time is more than 5
minutes.
On the other hand, when the treatment temperature is less than 900.degree.
C., the formation of the intermetallic compound of the hard film is
insufficient, and the quench- hardening of the substrate can not be
achieved. As a result, the stainless steel having the Vickers hardness of
400 or more can not be obtained. In addition, when using a slow cooling
rate of less than 1.degree. C./sec, the quench-hardening of the stainless
steel can not be achieved. It is preferred to-perform this quench
hardening treatment in vacuum, an inert gas atmosphere such as argon, or a
reducing gas atmosphere.
In the second method, a laminate is prepared by cladding the outer sheet of
Ti or the Ti alloy directly on one side or both sides of the martensite
stainless steel sheet without using the intermediate sheet. The Ti alloy
explained in the first method can be used in the second method. In
addition, a quench-hardening treatment of the second method is the same as
that of the first method. By this second method, the hard film having the
TiC layer, the TiFe.sub.2 layer formed on the TiC layer, and the TiFe
layer formed on the TiFe.sub.2 layer as the outermost layer is formed on
the stainless steel.
One of the first and second methods is selected according to the following
conditions.
(1) Thickness Ratio of Outer Sheet to Stainless Steel Sheet The thickness
ratio of the outer sheet (Ti or Ti alloy) to the stainless steel sheet in
the laminate can be expressed by the following equation:
.alpha. (%)=100.times.Ds/(Ds+DL)
wherein "Ds" is a one-half (1/2) thickness of the stainless steel sheet,
and "DL" is a thickness of the outer sheet on one side of the stainless
steel sheet in the laminate. When 85% >.alpha., the first method is
selected according to the following reason. In the heat treatment, a
titanium carbide such as TiC is generated by a reaction between Ti of the
outer sheet and C (carbon) contained in the stainless steel. When an
excess amount of carbon of the stainless steel is used to the reaction
with Ti, the quench-hardening effect to the stainless steel becomes to be
insufficient, so that the substrate having the Vickers hardness of 400 or
more can not be obtained. Therefore, in the first method, the intermediate
sheet of Ni, Fe, or the Ni--Cu alloy is inserted between the stainless
steel sheet and the outer sheet to control the generation of TiC.
Additionally, this intermediate sheet reacts with Ti of the outer sheet to
generate the intermetallic compound.
When the intermediate sheet of Fe is inserted, the Ti--Fe intermetallic
compound layer is formed in the hard film by the reaction of Fe of the
intermediate sheet with Ti during the heat treatment. Since this Ti--Fe
intermetallic compound layer is adhered to the stainless steel through a
diffusion layer formed by a mutual diffusion between Fe of the
intermediate sheet and components of the stainless steel, the adhesion
between the hard film and the stainless steel substrate is good. When the
thickness of the Fe intermediate sheet is thick, a thin Fe layer may
remain between the Ti--Fe intermetallic compound layer and this diffusion
layer. When the intermediate sheet of Ni is inserted, the Ti--Ni
intermetallic compound layer is formed in the hard film by the reaction of
Ni of the intermediate sheet with Ti during the heat treatment. Since this
Ti--Ni intermetallic compound layer is adhered to the stainless steel
through a diffusion layer formed by a mutual diffusion between Ni of the
intermediate sheet and components of the stainless steel, the adhesion
between the hard film and the stainless steel substrate is good. When the
thickness of the Ni intermediate sheet is thick, a thin Ni layer may
remain between the Ti--Ni intermetallic compound layer and this diffusion
layer.
In addition, when the intermediate sheet of the Ni--Cu alloy is inserted,
the mixture layer of the Ti--Ni intermetallic compound and the Ti--Cu
intermetallic compound is formed in the hard film by the reaction of Ni
and Cu of the intermediate sheet with Ti during the heat treatment. Since
this intermetallic compound layer is adhered to the stainless steel
through a diffusion layer formed by a mutual diffusion between Ni and Cu
of the intermediate sheet and components of the stainless steel, the
adhesion between the hard film and the stainless steel substrate is good.
When the thickness of the Ni--Cu alloy intermediate layer is thick, a thin
Ni--Cu alloy layer may remain between the intermetallic compound layer and
this diffusion layer.
On the other hand, when 85% .ltoreq..alpha., the second method is selected.
As described above, the generation of TiC is caused by the reaction between
Ti of the outer sheet and C (carbon) of the stainless steel during the
heat treatment. However, since the thickness of the outer sheet is much
thinner than that of the stainless steel, only a small amount of carbon of
the stainless steel is used for the TiC generation. This does not have an
influence upon the quench-hardening treatment. As a result, as shown in
FIG. 5, Ti of the outer sheet reacts with carbon of the stainless steel to
generate a thin TiC layer, and also reacts with Fe of the stainless steel
to generate the TiFe.sub.2 layer and the TiFe layer during the heat
treatment. An adhesion between the hard film and the stainless steel
substrate is good because a mutual diffusion between Ti of the outer sheet
and the components of the stainless steel is caused by the heat treatment.
(2) Carbon Content in Martensite Stainless Steel
In case that the carbon content in the martensite stainless steel is less
than 0.5 wt %, when carbon of the stainless steel is consumed by the TiC
generation during the heat treatment, it is difficult to achieve the
quench hardening treatment. Therefore, to control the reaction of Ti of
the outer sheet with carbon of the stainless steel, it is necessary to
insert the intermediate sheet of Fe, Ni, or the Ni--Cu alloy between the
stainless steel sheet and the outer sheet. For this reason, the first
method is selected. On the other hand, when the carbon content of the
stainless steel is 0.5 wt % or more, the quench hardening treatment can be
achieved even when carbon of the stainless steel is consumed to some
extent by the TiC generation during the heat treatment. Therefore, the use
of the intermediate sheet is not always required, so that the second
method is selected.
In the present specification, as an example, 85% of the thickness ratio
(.alpha.) and 5 % of the carbon content in the martensite stainless steel
are used as threshold values for deciding the use of either the first
method or the second method. However, the thickness ratio and the carbon
content are not always limited to these numerical values. According to the
actual shape and size of manufactured articles, some changes may be made
in those values.
Thus, in case of producing the intermetallic-compound coated stainless
steel of the present invention, when a decision that it will be difficult
to achieve the quench hardening treatment to obtain the substrate having
the Vickers hardness of 400 or more is brought by at least one of the
above items (1) and (2), the first method is selected.
In each of the first and second methods, it is preferred that the thickness
of the outer sheet in the laminate is within a range of 1 to 10 .mu.m. To
give excellent wear resistance to the intermetallic-compound coated
stainless steel, it is preferred that the thickness of the outer sheet is
1 .mu.m or more. In the first method using the intermediate sheet, it is
preferred that thickness of the intermediate sheet in the laminate is 1 to
3 times of that of the outer sheet.
In each of the first and second methods, when the heat treatment for
obtaining the hard film is performed after the laminate is worked to a
desired shape by. plastic deformation, for example, bending or drawing, it
is preferred to perform an annealing treatment to the laminate prior to
the plastic deformation. That is, due to work hardening caused by the
cladding, it is difficult to perform the plastic deformation to the
laminate. As the annealing treatment, the laminate is heated and kept at a
temperature of 700.degree. C. to 800.degree. C. for 15 seconds to 2
minutes, and then cooled.
When the annealing temperature is less than 700.degree. C., it is
insufficient to remove the work hardening from the laminate. When the
annealing temperature is more than 800.degree. C., there is a possibility
that cracks occur in a surface of the laminate during the plastic
deformation because the generation of the intermetallic compound begins in
the laminate. On the other hand, when the annealing time is less than 15
seconds, the work hardening can not be uniformly removed from the
laminate, and flaking or cracks easily occur during the plastic
deformation. When the annealing time is more than 2 minutes, there cause a
problem, which is the same as the problem occurring when the annealing
temperature is more than 800.degree. C.
EXAMPLES
The present invention is concretely explained according to the following
Examples. Compositions of stainless steel sheets and alloy sheets used in
the Examples are based on weight %. Layer thickness and hardness of an
intermetallic-compound coated stainless steel of each of the Examples and
Comparative Examples are shown in Tables 1 and 3. Producing conditions of
the intermetallic-compound coated stainless steels are shown in Tables 2
and 4.
EXAMPLE 1
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. A Ni sheet was placed on one side of the substrate,
and also a Ti sheet was placed on the Ni sheet. These piled-up sheets were
clad to the substrate by rolling to obtain a laminate. The laminate is
further rolled to adjust a total thickness of the laminate. As a result,
the total thickness of the laminate is 0.1 mm, in which a thickness of the
Ni sheet as an intermediate layer is 8 .mu.m, and a thickness of the Ti
sheet as an outer layer is 3 .mu.m. After an annealing treatment was
performed to the laminate at 700.degree. C. for 2 minutes, the laminate
was worked to a desired shape by bending. Subsequently, the worked
laminate was heated at 1050.degree. C. for 2 minutes in an atmosphere of
Ar (99.99%), and then cooled at a cooling rate of 50.degree. C./sec. By
this heat treatment, the stainless steel was quench-hardened to a Vickers
hardness of 600, and at the same time, a TiNi layer having a thickness of
3 .mu.m as an outermost layer, a TiNi.sub.3 layer having a thickness of 4
.mu.m formed under the TiNi layer as a second layer, and a diffusion layer
having a thickness of 4 .mu.m formed under the TiNi.sub.3 layer by a
mutual diffusion between the stainless steel and the Ni sheet, were
obtained on the stainless steel. FIG. 1 shows a result of EPMA performed
with respect to a depth direction from the laminate surface before the
heat treatment. FIG. 2 shows a result of EPMA performed with respect to
the depth direction from the laminate surface after the heat treatment.
FIG. 2 indicates that an atomic ratio of Ni:Ti of the outermost layer is
about 1:1, and the second layer having the atomic ratio of Ni:Ti of about
3:1 is formed under the outermost layer. In addition, a hardness change
measured in the depth direction from the surface of the hard film is shown
in FIG. 3.
EXAMPLE 2
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. Ni sheets were placed on both sides of the substrate,
and also Ti sheets were placed on the respective Ni sheets. These piled-up
sheets were clad to the substrate by rolling to obtain a laminate. The
laminate is further rolled to adjust a total thickness of the laminate. As
a result, the total thickness of the laminate is 0.05 mm, in which a
thickness of the Ni sheet as an intermediate layer is 5 .mu.m, and a
thickness of the Ti sheet as an outer layer is 3 .mu.m. After an annealing
treatment was performed to the laminate at 700.degree. C. for 30 seconds,
the laminate was worked to a desired shape by bending. Subsequently, the
worked laminate was heated at 1130.degree. C. for 30 seconds in an
atmosphere of Ar (99.99%), and then cooled at a cooling rate of 50.degree.
C./sec. By this heat treatment, the stainless steel was quench-hardened,
and at the same time, a TiNi layer having a thickness of 3 .mu.m as an
outermost layer, a TiNi.sub.3 layer having a thickness of 4 .mu.m formed
under the TiNi layer as a second layer, and a diffusion layer having a
thickness of 1 .mu.m formed under the TiNi.sub.3 layer by a mutual
diffusion between the stainless steel and the Ni sheet, were obtained on
the stainless steel.
EXAMPLE 3
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. Ni sheets were placed on both sides of the substrate,
and also Ti-0.2% Pd alloy sheets were placed on the respective Ni sheets.
These piled-up sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.1 mm,
in which a thickness of the Ni sheet as an intermediate layer is 13 .mu.m,
and a thickness of the Ti alloy sheet as an outer layer is 5 .mu.m. After
an annealing treatment was performed to the laminate at 750.degree. C. for
1 minute, the laminate was worked to a desired shape by drawing.
Subsequently, the worked laminate was heated at 1000.degree. C. for 5
minutes in an atmosphere of Ar (99.99%), and then cooled at a cooling rate
of 1.degree. C./sec. By this heat treatment, the stainless steel was
quench-hardened, and at the same time, a TiNi layer having a thickness of
5 .mu.m as an outermost layer, a TiNi.sub.3 layer having a thickness of 7
.mu.m formed under the TiNi layer as a second layer, and a diffusion layer
having a thickness of 7 .mu.m formed under the TiNi.sub.3 layer by a
mutual diffusion between the stainless steel and the Ni sheet, were
obtained on the stainless steel.
EXAMPLE 4
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. Ni sheets were placed on both sides of the substrate,
and also Ti sheets were placed on the respective Ni sheets. These piled-up
sheets were clad to the substrate by rolling to obtain a laminate. The
laminate is further rolled to adjust a total thickness of the laminate. As
a result, the total thickness of the laminate is 0.08 mm, in which a
thickness of the Ni sheet as an intermediate layer is 6 .mu.m, and a
thickness of the Ti sheet as an outer layer is 3 .mu.m. After an annealing
treatment was performed to the laminate at 800.degree. C. for 15 seconds,
the laminate was worked to a desired shape by bending. Subsequently, the
worked laminate was heated at 930.degree. C. for 5 minutes in an
atmosphere of Ar (99.99%), and then cooled at a cooling rate of 20.degree.
C./sec. By this heat treatment, the stainless steel was quench-hardened,
and at the same time, a TiNi layer having a thickness of 3 .mu.m as an
outermost layer, a TiNi.sub.3 layer having a thickness of 4 .mu.m formed
under the TiNi layer as a second layer, and a diffusion layer having a
thickness of 3 .mu.m formed under the TiNi.sub.3 layer by a mutual
diffusion between the stainless steel and the Ni sheet, were obtained on
the stainless steel.
EXAMPLE 5
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. Ni sheets were placed on both sides of the substrate,
and also Ti sheets were placed on the respective Ni sheets. These piled-up
sheets were clad to the substrate by rolling to obtain a laminate. The
laminate is further rolled to adjust a total thickness of the laminate. As
a result, the total thickness of the laminate is 0.1 mm, in which a
thickness of the Ni sheet as an intermediate layer is 3 .mu.m, and a
thickness of the Ti sheet as an outer layer is 3 .mu.m. After an annealing
treatment was performed to the laminate at 800.degree. C. for 30 seconds,
the laminate was worked to a desired shape by drawing. Subsequently, the
worked laminate was heated at 1000.degree. C. for 2 minutes in an
atmosphere of Ar (99.99%), and then cooled at a cooling rate of 10.degree.
C./sec. By this heat treatment, the stainless steel was quench-hardened,
and at the same time, a TiNi layer having a thickness of 2 .mu.m as an
outermost layer, a TiNi.sub.3 layer having a thickness of 3 .mu.m formed
under the TiNi layer as a second layer, and a diffusion layer having a
thickness of 1 .mu.m formed under the TiNi.sub.3 layer by a mutual
diffusion between the stainless steel and the Ni sheet, were obtained on
the stainless steel.
EXAMPLE 6
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. Ni sheets were placed on both sides of the substrate,
and also Ti sheets were placed on the respective Ni sheets. These piled-up
sheets were clad to the substrate by rolling to obtain a laminate. The
laminate is further rolled to adjust a total thickness of the laminate. As
a result, the total thickness of the laminate is 0.1 mm, in which a
thickness of the Ni sheet as an intermediate layer is 5 .mu.m, and a
thickness of the Ti sheet as an outer layer is 3 .mu.m. After an annealing
treatment was performed to the laminate at 800.degree. C. for 1 minute,
the laminate was worked to a desired shape by bending. Subsequently, the
worked laminate was heated at 1050.degree. C. for 2 minutes in an
atmosphere of Ar (99.99%), and then cooled at a cooling rate of 5.degree.
C./sec. By this heat treatment, the stainless steel was quench-hardened,
and at the same time, a TiNi layer having a thickness of 3 .mu.m as an
outermost layer, a TiNi.sub.3 layer having a thickness of 4 .mu.m formed
under the TiNi layer as a second layer, and a diffusion layer having a
thickness of 1 .mu.m formed under the TiNi.sub.3 layer by a mutual
diffusion between the stainless steel and the Ni sheet, were obtained on
the stainless steel.
EXAMPLE 7
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. Ni sheets were placed on both sides of the substrate,
and also Ti sheets were placed on the respective Ni sheets. These piled-up
sheets were clad to the substrate by rolling to obtain a laminate. The
laminate is further rolled to adjust a total thickness of the laminate. As
a result, the total thickness of the laminate is 0.2 mm, in which a
thickness of the Ni sheet as an intermediate layer is 35 .mu.m, and a
thickness of the Ti sheet as an outer layer is 10 .mu.m. Subsequently, the
laminate was heated at 1050.degree. C. for 3 minutes in an atmosphere of
Ar (99.99%), and then cooled at a cooling rate of 10.degree. C./sec. By
this heat treatment, the stainless steel was quench-hardened, and at the
same time, a TiNi layer having a thickness of 10 .mu.m as an outermost
layer, a TiNi.sub.3 layer having a thickness of 12 .mu.m formed under the
TiNi layer as a second layer, and a diffusion layer having a thickness of
23 .mu.m formed under the TiNi.sub.3 layer by a mutual diffusion between
the stainless steel and the Ni sheet, were obtained on the stainless
steel.
EXAMPLE 8
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. Fe sheets were placed on both sides of the substrate,
and also Ti sheets were placed on the respective Fe sheets. These piled-up
sheets were clad to the substrate by rolling to obtain a laminate. The
laminate is further rolled to adjust a total thickness of the laminate. As
a result, the total thickness of the laminate is 0.05 mm, in which a
thickness of the Fe sheet as an intermediate layer is 4 .mu.m, and a
thickness of the Ti sheet as an outer layer is 4 .mu.m. After an annealing
treatment was performed to the laminate at 800.degree. C. for 30 seconds,
the laminate was worked to a desired shape by drawing. Subsequently, the
worked laminate was heated at 950.degree. C. for 2 minutes in an
atmosphere of Ar (99.99%), and then cooled at a cooling rate of 10.degree.
C./sec. By this heat treatment, the stainless steel was quench-hardened,
and at the same time, a TiFe layer having a thickness of 4 .mu.m as an
outermost layer, a TiFe.sub.2 layer having a thickness of 3 .mu.m formed
under the TiFe layer as a second layer, and a diffusion layer having a
thickness of 1 .mu.m formed under the TiFe.sub.2 layer by a mutual
diffusion between the stainless steel and the Fe sheet, were obtained on
the stainless steel.
EXAMPLE 9
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. Fe sheets were placed on both sides of the substrate,
and also Ti sheets were placed on the respective Fe sheets. These piled-up
sheets were clad to the substrate by rolling to obtain a laminate. The
laminate is further rolled to adjust a total thickness of the laminate. As
a result, the total thickness of the laminate is 0.1 mm, in which a
thickness of the Fe sheet as an intermediate layer is. 8 .mu.m, and a
thickness of the Ti sheet as an outer layer is 4 .mu.m. After an annealing
treatment was performed to the laminate at 750.degree. C. for 1 minute,
the laminate was worked to a desired shape by bending. Subsequently, the
worked laminate was heated at 1050.degree. C. for i minute in an
atmosphere of Ar (99.99%), and then cooled at a cooling rate of 5.degree.
C./sec. By this heat treatment, the stainless steel was quench-hardened,
and at the same time, a TiFe layer having a thickness of 4 .mu.m as an
outermost layer, a TiFe.sub.2 layer having a thickness of 5 .mu.m formed
under the TiFe layer as a second layer, and a diffusion layer having a
thickness of 3 .mu.m formed under the TiFe.sub.2 layer by a mutual
diffusion between the stainless steel and the Fe sheet, were obtained on
the stainless steel.
EXAMPLE 10
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. Fe sheets were placed on both sides of the substrate,
and also Ti sheets were placed on the respective Fe sheets. These piled-up
sheets were clad to the substrate by rolling to obtain a laminate. The
laminate is further rolled to adjust a total thickness of the laminate. As
a result, the total thickness of the laminate is 0.3 mm, in which a
thickness of the Fe sheet as an intermediate layer is 25 .mu.m, and a
thickness of the Ti sheet as an outer layer is 10 .mu.m. After an
annealing treatment was performed to the laminate at 800.degree. C. for 2
minutes, the laminate was worked to a desired shape by bending.
Subsequently, the worked laminate was heated at 1150.degree. C. for 30
seconds in an atmosphere of Ar (99.99%), and then cooled at a cooling rate
of 10 .degree. C./sec. By this heat treatment, the stainless steel was
quench-hardened, and at the same time, a TiFe layer having a thickness of
10 .mu.m as an outermost layer, a TiFe.sub.2 layer having a thickness of 9
.mu.m formed under the TiFe layer as a second layer, and a diffusion layer
having a thickness of 6 .mu.m formed under the TiFe.sub.2 layer by a
mutual diffusion between the stainless steel and the Fe sheet, were
obtained on the stainless steel.
EXAMPLE 11
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. A Ni-20% Cu alloy sheet was placed on one side of the
substrate, and also a Ti sheet was placed on the alloy sheet. These
piled-up sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.05 mm,
in which a thickness of the Ni-20% Cu alloy sheet as an intermediate layer
is 5 .mu.m, and a thickness of the Ti sheet as an outer layer is 2 .mu.m.
Subsequently, the laminate was heated at 1050.degree. C. for 2 minutes in
an atmosphere of Ar (99.99%), and then cooled at a cooling rate of
25.degree. C./sec. By this heat treatment, the stainless steel was
quench-hardened, and at the same time, a mixture layer of TiNi and TiCu
having a thickness of 2 .mu.m as an outermost layer, a mixture layer of
TiNi.sub.3, Ti.sub.2 Cu.sub.3, and TiCu.sub.2 having a thickness of 3
.mu.m formed under the outermost layer as a second layer, and a diffusion
layer having a thickness of 2 .mu.m formed under the second layer by a
mutual diffusion between the stainless steel and the Ni--Cu alloy sheet,
were obtained on the stainless steel.
EXAMPLE 12
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. A Ni--25% Cu alloy sheet was placed on one side of
the substrate, and also a Ti-0.2% Pd alloy sheet was placed on the Ni--Cu
alloy sheet. These piled-up sheets were clad to the substrate by rolling
to obtain a laminate. The laminate is further rolled to adjust a total
thickness of the laminate. As a result, the total thickness of the
laminate is 0.09 mm, in which a thickness of the Ni--Cu alloy sheet as an
intermediate layer is 4 .mu.m, and a thickness of the Ti--Pd alloy sheet
as an outer layer is 4 .mu.m. Subsequently, the laminate was heated at
1000.degree. C. for 30 seconds in an atmosphere of Ar (99.99%), and then
cooled at a cooling rate of 1.degree. C./sec. By this heat treatment, the
stainless steel was quench-hardened, and at the same time, a mixture layer
of TiNi and TiCu having a thickness of 3 .mu.m as an outermost layer, a
mixture layer of TiNi.sub.3, Ti.sub.2 Cu.sub.3, and TiCu.sub.2 having a
thickness of 4 .mu.m formed under the outermost layer as a second layer,
and a diffusion layer having a thickness of 1 .mu.m formed under the
second layer by a mutual diffusion between the stainless steel and the
Ni--Cu alloy sheet, were obtained on the stainless steel.
EXAMPLE 13
A martensite stainless steel having the composition shown in Table 1 was
used as a substrate. A Ni-15% Cu alloy sheet was placed on one side of the
substrate, and also a Ti sheet was placed on the Ni--Cu alloy sheet. These
piled-up sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.04 mm,
in which a thickness of the Ni--Cu alloy sheet as an intermediate layer is
8 .mu.m, and a thickness of the Ti sheet as an outer layer is 2 .mu.m.
Subsequently, the laminate was heated at 1100.degree. C. for 5 minutes in
an atmosphere of Ar (99.99%), and then cooled at a cooling rate of
10.degree. C./sec. By this heat treatment, the stainless steel was
quench-hardened, and at the same time, a mixture layer of TiNi and TiCu
having a thickness of 2 .mu.m as an outermost layer, a mixture layer of
TiNi.sub.3, Ti.sub.2 Cu.sub.3, and TiCu.sub.2 having a thickness of 3
.mu.m formed under the outermost layer as a second layer, and a diffusion
layer having a thickness of 5 .mu.m formed under the second layer by a
mutual diffusion between the stainless steel and the Ni--Cu alloy sheet,
were obtained on the stainless steel.
COMPARATIVE EXAMPLE 1
The same laminate as Example 2 was prepared. After the same annealing
treatment as Example 2 was performed to the laminate, the laminate was
worked to a desired shape by bending. Subsequently, the laminate was
heated at 1170.degree. C. for 30 seconds in an atmosphere of Ar (99.99%),
and then cooled at a cooling rate of 50.degree. C./sec. By this heat
treatment, a TiNi layer having a thickness of 3 .mu.m as an outermost
layer, and a TiNi.sub.3 layer having a thickness of 4 .mu.m formed under
the TiNi layer as a second layer were obtained on the stainless steel.
However, the generation of a diffusion layer was not observed between the
TiNi.sub.3 layer and the stainless steel. In addition, the stainless steel
was not quench-hardened to a Vickers hardness of 400 or more. As the
reason, it is believed that since the heat treatment temperature is higher
than 1150.degree. C., Ti of an outer layer diffused into the stainless
steel through an intermediate layer of Ni, and reacted with carbon of the
stainless steel, so that the carbon content in the stainless steel
decreased.
COMPARATIVE EXAMPLE 2
The same laminate as Example 2 was prepared. After the same annealing
treatment as Example 2 was performed to the laminate, the laminate was
worked to a desired shape by bending. Subsequently, the laminate was
heated at 850.degree. C. for 5 minutes in an atmosphere of Ar (99.99%),
and then cooled at a cooling rate of 50.degree. C./sec. By this heat
treatment, a TiNi layer having a thickness of 2 .mu.m as an outermost
layer, a TiNi.sub.3 layer having a thickness of 3 .mu.m formed under the
TiNi layer, and a diffusion-layer having a thickness of 3 .mu.m formed
under the TiNi.sub.3 layer by a mutual diffusion between the stainless
steel and the Ni sheet, were obtained on the stainless steel. However,
since the thermal treatment was performed at such a low temperature, the
stainless steel could not be quench-hardened to a Vickers hardness of 400
or more.
COMPARATIVE EXAMPLE 3
The same laminate as Example 2 was prepared. After the same annealing
treatment as Example 2 was performed to the laminate, the laminate was
worked to a desired shape by bending. Subsequently, the laminate was
heated at 1050.degree. C. for 15 seconds in an atmosphere of Ar (99.99%),
and then cooled at a cooling rate of 50.degree. C./sec. By this heat
treatment, a TiNi layer having a thickness of 2 .mu.m as an outermost
layer, a TiNi.sub.3 layer having a thickness of 3 .mu.m formed under the
TiNi layer, and a diffusion layer having a thickness of 3 .mu.m formed
under the TiNi.sub.3 layer by a mutual diffusion between the stainless
steel and the Ni sheet, were obtained on the stainless steel. However,
since the thermal treatment was performed for such a short time period,
the laminate could not be uniformly heated. As a result, the stainless
steel could not be quench-hardened to a Vickers hardness of 400 or more.
COMPARATIVE EXAMPLE 4
The same laminate as Example 2 was prepared. After the same annealing
treatment as Example 2 was performed to the laminate, the laminate was
worked to a desired shape by bending. Subsequently, the laminate was
heated at 1050.degree. C. for 8 minutes in an atmosphere of Ar (99.99%),
and then cooled at a cooling rate of 50.degree. C./sec. By this heat
treatment, a TiNi layer having a thickness of 3 .mu.m as an outermost
layer, and a TiNi.sub.3 layer having a thickness of 4 .mu.m formed under
the TiNi layer were obtained on the stainless steel. However, the
generation of a diffusion layer was not observed between the TiNi.sub.3
layer and the stainless steel. In addition, the stainless steel was not
quench-hardened to a Vickers hardness of 400 or more. As the reason, it is
believed that since the thermal treatment was performed at 1050.degree. C.
for such an extended time period, Ti of an outer layer diffused into the
stainless steel through an intermediate layer of Ni, and reacted with
carbon of the stainless steel, so that the carbon content in the stainless
steel decreased.
COMPARATIVE EXAMPLE 5
The same laminate as Example 2 was prepared. After an annealing treatment
was performed to the laminate at 650.degree. C. for 2 minutes in an
atmosphere of Ar (99.99%), the laminate was worked to a desired shape by
bending. However, since work hardening caused by the rolling at the
preparation of the laminate was not sufficiently removed from the laminate
by the annealing treatment, cracks occurred at the worked portions of the
laminate. Therefore, a heat treatment for forming a hard film was not
carried out.
COMPARATAIVE EXAMPLE 6
The same laminate as Example 2 was prepared. After an annealing treatment
was performed to the laminate at 850.degree. C. for 5 seconds in an
atmosphere of Ar (99.99%), the laminate was worked to a desired shape by
drawing. However, since work hardening caused by the rolling at the
preparation of the laminate was not sufficiently removed from the laminate
by the annealing treatment, cracks occurred at the worked portions of the
laminate. Therefore, a heat treatment for forming a hard film was not
carried out.
COMPARATIVE EXAMPLE 7
The same laminate as Example 2 was prepared. After the same annealing
treatment as Example 2 was performed to the laminate, the laminate was
worked to a desired shape by bending. Subsequently, the laminate was
heated at 1130.degree. C. for 30 seconds in an atmosphere of Ar (99.99%),
and then cooled at a cooling rate of 0.5.degree. C./sec. By this heat
treatment, a TiNi layer having a thickness of 3 .mu.m as an outermost
layer, a TiNi.sub.3 layer having a thickness of 4 .mu.m formed under the
TiNi layer, and a diffusion layer having a thickness of 1 .mu.m formed
under the TiNi.sub.3 layer by a mutual diffusion between the stainless
steel and the Ni sheet, were obtained on the stainless steel. However,
since the cooling rate was too slow, the stainless steel could not be
quench-hardened to a Vickers hardness of 400 or more.
EXAMPLE 14
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.2 mm,
in which a thickness of the Ti sheet is 5 .mu.m. Subsequently, the
laminate was heated at 950.degree. C. for 1 minute in an atmosphere of Ar
(99.99%), and then cooled at a cooling rate of about 300.degree. C./sec.
By this heat treatment, the stainless steel was quench-hardened to a
Vickers hardness of 400 or more, and at the same time, a hard film
composed of a TiC layer having a thickness of 1 .mu.m, a TiFe.sub.2 layer
having a thickness of 2 .mu.m formed on the TiC layer, and a TiFe layer
having a thickness of 2 .mu.m formed on the TiFe.sub.2 layer, was obtained
on the stainless steel.
EXAMPLE 15
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.1 mm,
in which a thickness of the Ti sheet is 4 .mu.m. After an annealing
treatment was performed to the laminate at 700.degree. C. for 2 minutes in
an Ar gas atmosphere, the laminate was worked to a desired shape by
bending. Subsequently, the worked laminate was heated at 950.degree. C.
for 1 minute, and then cooled at a cooling rate of 2.degree. C./sec. By
this heat treatment, the stainless steel was quench-hardened, and at the
same time, a hard film composed of a TiC layer having a thickness of 1
.mu.m, a TiFe.sub.2 layer having a thickness of 1 .mu.m formed on the TiC
layer, and a TiFe layer having a thickness of 2 .mu.m formed on the
TiFe.sub.2 layer, was obtained on the stainless steel.
EXAMPLE 16
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.05 mm,
in which a thickness of the Ti sheet is 3 .mu.m. After an annealing
treatment was performed to the laminate at 800.degree. C. for 30 seconds
in an Ar gas atmosphere, the laminate was worked to a desired shape by
drawing. Subsequently, the worked laminate was heated at 1100.degree. C.
for 30 seconds, and then cooled at a cooling rate of 100.degree. C./sec.
By this heat treatment, the stainless steel was quench-hardened, and at
the same time, a hard film composed of a TiC layer having a thickness of 1
.mu.m, a TiFe.sub.2 layer having a thickness of 1 .mu.m formed on the TiC
layer, and a TiFe layer having a thickness of 1 .mu.m formed on the
TiFe.sub.2 layer, was obtained on the stainless steel.
EXAMPLE 17
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.4 mm,
in which a thickness of the Ti sheet is 10 .mu.m. After an annealing
treatment was performed to the laminate at 700.degree. C. for 2 minutes in
an Ar gas atmosphere, the laminate was worked to a desired shape by
drawing. Subsequently, the worked laminate was heated at 950.degree. C.
for 5 minutes, and then cooled at a cooling rate of 7.degree. C./sec. By
this heat treatment, the stainless steel was quench-hardened, and at the
same time, a hard film composed of a TiC layer having a thickness of 1
.mu.m, a TiFe.sub.2 layer having a thickness of 4 .mu.m formed on the TiC
layer, and a TiFe layer having a thickness of 5 .mu.m formed on the
TiFe.sub.2 layer, was obtained on the stainless steel.
EXAMPLE 18
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 1 mm, in
which a thickness of the Ti sheet is 12 .mu.m. Subsequently, the laminate
was heated at 1050.degree. C. for 2 minutes, and then cooled at a cooling
rate of 50.degree. C./sec. By this heat treatment, the stainless steel was
quench-hardened, and at the same time, a hard film composed of a TiC layer
having a thickness of 1 .mu.m, a TiFe.sub.2 layer having a thickness of 5
.mu.m formed on the TiC layer, and a TiFe layer having a thickness of 6
.mu.m formed on the TiFe.sub.2 layer, was obtained on the stainless steel.
EXAMPLE 19
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.04 mm,
in which a thickness of the Ti sheet is 3 .mu.m. Subsequently, the
laminate was heated at 1100.degree. C. for 30 seconds, and then cooled at
a cooling rate of 20.degree. C./sec. By this heat treatment, the stainless
steel was quench-hardened, and at the same time, a hard film composed of a
TiC layer having a thickness of 1 .mu.m, a TiFe.sub.2 layer having a
thickness of 1 .mu.m formed on the TiC layer, and a TiFe layer having a
thickness of 1 .mu.m formed on the TiFe.sub.2 layer, was obtained on the
stainless steel.
EXAMPLE 20
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.2 mm,
in which a thickness of the Ti sheet is 4 .mu.m. Subsequently, the
laminate was heated at 1000.degree. C. for 1 minute in an Ar gas
atmosphere, and then cooled at a cooling rate of 10.degree. C./sec. By
this heat treatment, the stainless steel was quench-hardened, and at the
same time, a hard film composed of a TiC layer having a thickness of 1
.mu.m, a TiFe.sub.2 layer having a thickness of 1 .mu.m formed on the TiC
layer, and a TiFe layer having a thickness of 2 .mu.m formed on the
TiFe.sub.2 layer, was obtained on the stainless steel.
EXAMPLE 21
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti--0.2% Pd alloy sheets were placed directly on both
sides of the substrate. The Ti--Pd alloy sheets were clad to the substrate
by rolling to obtain a laminate. The laminate is further rolled to adjust
a total thickness of the laminate. As a result, the total thickness of the
laminate is 0.08 mm, in which a thickness of the Ti--Pd alloy sheet is 5
.mu.m. Subsequently, the laminate was heated at 1000.degree. C. for 30
seconds in an Ar gas atmosphere, and then cooled at a cooling rate of
50.degree. C./sec. By this heat treatment, the stainless steel was
quench-hardened, and at the same time, a hard film composed of a TiC layer
having a thickness of 1 .mu.m, a TiFe.sub.2 layer having a thickness of 2
.mu.m formed on the TiC layer, and a TiFe layer having a thickness of 2
.mu.m formed on the TiFe.sub.2 layer, was obtained on the stainless steel.
EXAMPLE 22
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.1 mm,
in which a thickness of the Ti sheet is 7 .mu.m. Subsequently, the
laminate was heated at 1050.degree. C. for 1 minute in an Ar gas
atmosphere, and then cooled at a cooling rate of about 300.degree. C./sec.
By this heat treatment, the stainless steel was quench-hardened, and at
the same time, a hard film composed of a TiC layer having a thickness of 1
.mu.m, a TiFe.sub.2 layer having a thickness of 3 .mu.m formed on the TiC
layer, and a TiFe layer having a thickness of 3 .mu.m formed on the
TiFe.sub.2 layer, was obtained on the stainless steel. FIG. 4 shows a SEM
photograph of a cross section of an intermetallic-compound coated
stainless steel of this Example. FIG. 5 shows a SEM photograph of an
interface portion between the stainless steel and the hard film of this
Example. FIGS. 6 to 9 respectively show distributions of Fe, Cr, Ti and C
concentrations measured at the interface portion of FIG. 5. These figures
suggest that the TiC layer be formed between the Ti--Fe intermetallic
compound layer and the substrate.
EXAMPLE 23
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the 15 laminate is 0.2
mm, in which a thickness of the Ti sheet is 10 .mu.m. Subsequently, the
laminate was heated at 1120.degree. C. for 2 minute in an Ar gas
atmosphere, and then cooled at a cooling rate of 2.degree. C./sec. By this
heat treatment, the stainless steel was quench-hardened, and at the same
time, a hard film composed of a TiC layer having a thickness of 2 .mu.m, a
TiFe.sub.2 layer having a thickness of 4 .mu.m formed on the TiC layer,
and a TiFe layer having a thickness of 5 .mu.m formed on the TiFe.sub.2
layer, was obtained on the stainless steel.
COMPARATIVE EXAMPLE 8
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.1 mm,
in which a thickness of the Ti sheet is 10 .mu.m. Subsequently, the
laminate was heated at 1100.degree. C. for 7 minutes in an Ar gas
atmosphere, and then cooled at a cooling rate of 10.degree. C./sec. By
this heat treatment, a hard film composed of a TiC layer having a
thickness of 2 .mu.m, a TiFe.sub.2 layer having a thickness of 4 .mu.m
formed on the TiC layer, and a TiFe layer having a thickness of 5 .mu.m
formed on the TiFe.sub.2 layer, was obtained on the stainless steel.
However, the stainless steel could not be quench-hardened to a Vickers
hardness of 400 or more. As a reason for the inconvenience, it is believed
that a reaction between carbon of the stainless steel and Ti excessively
proceeded for such an extended time period of the heat treatment, so that
the carbon content in the stainless steel decreased.
COMPARATIVE EXAMPLE 9
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.1 mm,
in which a thickness of the Ti sheet is 2 .mu.m. Subsequently, the
laminate was heated at 1050.degree. C. for 15 seconds in an Ar gas
atmosphere, and then cooled at a cooling rate of 10.degree. C./sec. By
this heat treatment, a TiC layer having a thickness of 0.5 .mu.m was
obtained on the stainless steel. However, no intermetallic compound layer
between Ti and Fe was confirmed. In addition, since the thermal treatment
was performed for such a short time, the laminate could not be uniformly
heated. By this reason, the stainless steel could not be quench-hardened
to a Vickers hardness of 400 or more.
COMPARATIVE EXAMPLE 10
The same laminate as Comparative Example 8 was prepared. The laminate was
heated at 870.degree. C. for 5 minutes, and then cooled at a cooling rate
of 10.degree. C./sec. By this heat treatment, a hard film composed of a
TiC layer having a thickness of 0.5 .mu.m, a TiFe.sub.2 layer having a
thickness of 3 .mu.m formed on the TiC layer, and a TiFe layer having a
thickness of 3 .mu.m formed on the TiFe.sub.2 layer, was obtained on the
stainless steel. However, since the thermal treatment was performed at
such a low temperature, the stainless steel could not be quench-hardened
to a Vickers hardness of 400 or more.
COMPARATIVE EXAMPLE 11
The same laminate as Comparative Example 8 was prepared. The laminate was
heated at 1170.degree. C. for 30 seconds, and then cooled at a cooling
rate of 10.degree. C./sec. By this heat treatment, a hard film composed of
a TiC layer having a thickness of 2 .mu.m, a TiFe.sub.2 layer having a
thickness of 3 .mu.m formed on the TiC layer, and a TiFe layer having a
thickness of 5 .mu.m formed on the TiFe.sub.2 layer, was obtained on the
stainless steel. However, the stainless steel could not be quench-hardened
to a Vickers hardness of 400 or more. As a reason for the inconvenience,
it is believed that since the heat treatment was performed at such a high
temperature more than 1150.degree. C., an excess amount of Ti diffused
into the stainless steel and reacted with carbon of the stainless steel,
so that the carbon content in the stainless steel decreased.
COMPARATIVE EXAMPLE 12
The same laminate as Comparative Example 8 was prepared. The laminate was
heated at 1050.degree. C. for 2 minutes, and then cooled at a cooling rate
of 0.5.degree. C./sec. By this heat treatment, a hard film composed of a
TiC layer having a thickness of 1 .mu.m, a TiFe.sub.2 layer having a
thickness of 4 .mu.m formed on the TiC layer, and a TiFe layer having a
thickness of 5 .mu.m formed on the TiFe.sub.2 layer, was obtained on the
stainless steel. However, since the cooling rate was too slow, the
stainless steel could not be quench-hardened to a Vickers hardness of 400
or more.
COMPARATIVE EXAMPLE 13
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.05 mm,
in which a thickness of the Ti sheet is 3 .mu.m. After an annealing
treatment was performed to the laminate at 850.degree. C. for 1 minute in
an Ar gas atmosphere, the laminate was worked to a desired shape by
bending. However, cracks occurred at the worked portions of the laminate.
As a reason for this inconvenience, it is believed that since the
annealing treatment was performed at such a high temperature more than
800.degree. C., the formation of a TiC layer and an intermetallic compound
proceeded in the laminate, so that the laminate could not sustain the
plastic deformation. Therefore, a subsequent heat treatment for forming a
hard film was performed.
COMPARATIVE EXAMPLE 14
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.1 mm,
in which a thickness of the Ti sheet is 4 .mu.m. After an annealing
treatment was performed to the laminate at 650.degree. C. for 2 minutes in
an Ar gas atmosphere, the laminate was worked to a desired shape by
bending. However, cracks occurred at the worked portions of the laminate.
As a reason for this inconvenience, it is believed that since the
annealing temperature was too low, work hardening caused by the rolling at
the preparation of the laminate was not sufficiently removed from the
laminate, so that the cracks occurred at the worked portions. Therefore, a
subsequent heat treatment for forming a hard film was performed.
COMPARATIVE EXAMPLE 15
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.05 mm,
in which a thickness of the Ti sheet is 3 .mu.m. After an annealing
treatment was performed to the laminate at 700.degree. C. for 5 minutes in
an Ar gas atmosphere, the laminate was worked to a desired shape by
bending. However, cracks occurred at the worked portions of the laminate.
As a reason for this inconvenience, it is believed that since the
annealing treatment was performed at 700.degree. C. for such an extended
time period, the formation of a TiC layer and an intermetallic compound
proceeded in the laminate, so that the laminate could not sustain the
plastic deformation. Therefore, a subsequent heat treatment for forming a
hard film was performed.
COMPARATIVE EXAMPLE 16
A martensite stainless steel having the composition shown in Table 3 was
used as a substrate. Ti sheets were placed directly on both sides of the
substrate. The Ti sheets were clad to the substrate by rolling to obtain a
laminate. The laminate is further rolled to adjust a total thickness of
the laminate. As a result, the total thickness of the laminate is 0.1 mm,
in which a thickness of the Ti sheet is 4 .mu.m. After an annealing
treatment was performed to the laminate at 700.degree. C. for 5 seconds in
an Ar gas atmosphere, the laminate was worked to a desired shape by
bending. However, cracks occurred at the worked portions of the laminate.
As a reason for this inconvenience, it is believed that since the
annealing time was too short, work hardening caused by the rolling at the
preparation of the laminate was not sufficiently removed from the
laminate, so that the cracks occurred at the worked portions. Therefore, a
subsequent heat treatment for forming a hard film was performed.
As shown in Examples 1 to 23, by the method of producing the
intermetallic-compound coated stainless steel of the present invention,
the martensite stainless steel substrate can be quench-hardened to a
Vickers hardness of 400 or more, and a hard film having an outermost layer
selected from the group consisting of the Ti--Ni intermetallic compound
layer, Ti--Fe intermetallic compound layer, and the mixture layer of the
Ti--Ni intermetallic compound and the Ti--Cu intermetallic compound, can
be formed on the quench-hardened substrate. Since the hard film has a
Vickers hardness of 800 or more and is excellent in corrosion resistance,
the combination of the quench-hardened substrate and the hard film is
suitable for structural parts such as gears and bearings, and cutting
tools such as hair clippers and blades for electric shavers.
On the other hand, as shown in Comparative Examples 1 to 5 and 8 to 12,
when the heat treatment condition is not adequately selected, the
stainless steel substrate can not be quench-hardened to the Vickers
hardness of 400 or more. In addition, when the laminate is worked to a
desired shape by plastic deformation prior to the heat treatment for
forming the hard film, it is necessary to perform an annealing treatment
characterized by heating the laminate at 700 to 800.degree. C. for 15
seconds to 2 minutes prior to the plastic deformation. The annealing
treatment is useful to remove the work hardening from the laminate. As
shown in Comparative Examples 6, 7, and 13 to 16, when the annealing
treatment condition is not adequately selected, cracks will occur in the
laminate. Thus, the annealing treatment is important in the method of
producing the intermetallic-compound coated stainless steel of the present
invention.
TABLE 1
Thickness Structure of Hard
Film Substrate Hardness
Composition of Martensite Stainless of Diffusion Outermost
Layer Second Layer Hardness of Hard
Steel (wt %) Layer (Thickness)
(Thickness) Hv Film Hv
Example 1 Fe-13.5 Cr-1.2 Mo-0.4 C-0.3 Si-0.3 Mn 4 .mu.m TiNi (3 .mu.m)
TiNi.sub.3 (4 .mu.m) 600 1100
Example 2 Fe-13.5 Cr-1.2 Mo-0.4 C-0.3 Si-0.3 Mn 1 .mu.m TiNi (3 .mu.m)
TiNi.sub.3 (4 .mu.m) 600 1200
Example 3 Fe-15.5 Cr-1.0 Mo-0.5 C 7 .mu.m TiNi (5 .mu.m)
TiNi.sub.3 (7 .mu.m) 550 1000
Example 4 Fe-13.5 Cr-1.2 Mo-0.3 C 3 .mu.m TiNi (3 .mu.m)
TiNi.sub.3 (4 .mu.m) 500 1000
Example 5 Fe-19.5 Cr-0.3 C 1 .mu.m TiNi (2 .mu.m)
TiNi.sub.3 (3 .mu.m) 500 900
Example 6 Fe-13.0 Cr-0.8 C 1 .mu.m TiNi (3 .mu.m)
TiNi.sub.3 (4 .mu.m) 650 1100
Example 7 Fe-13.5 Cr-1.0.Mo-0.5 C 23 .mu.m TiNi (10 .mu.m)
TiNi.sub.3 (12 .mu.m) 550 950
Example 8 Fe-13.5 Cr-1.2 Mo-0.4 C 1 .mu.m TiFe (4 .mu.m)
TiFe.sub.2 (3 .mu.m) 500 900
Example 9 Fe-15.5 Cr-1.0 Mo-0.5 C 3 .mu.m TiFe (4 .mu.m)
TiFe.sub.2 (5 .mu.m) 600 950
Example 10 Fe-13.5 Cr-1.2 Mo-0.4 C-0.3 Si-0.3 Mn 6 .mu.m TiFe (10 .mu.m)
TiFe.sub.2 (9 .mu.m) 600 850
Example 11 Fe-15.5 Cr-1.0 Mo-0.5 C 2 .mu.m TiNi + TiCu (2 .mu.m)
TiNi.sub.3 + TiCu.sub.2 + Ti.sub.2 Cu.sub.3 600 1100
(3 .mu.m)
Example 12 Fe-15.5 Cr-0.5 Mo-0.5 C 1 .mu.m TiNi + TiCu (3 .mu.m)
TiNi.sub.3 + TiCu.sub.2 + Ti.sub.2 Cu.sub.3 500 1000
(4 .mu.m)
Example 13 Fe-13.5 Cr-0.8 Mo-0.4 C 5 .mu.m TiNi + TiCu (2 .mu.m)
TiNi.sub.3 + TiCu.sub.2 + Ti.sub.2 Cu.sub.3 550 1000
(3 .mu.m)
Comparative Fe-13.5 Cr-1.2 Mo-0.4 C-0.3 Si-0.3 Mn 0 TiNi (3 .mu.m)
TiNi.sub.3 (4 .mu.m) 350 1000
Example 1
Comparative Fe-13.5 Cr-1.2 Mo-0.4 C-0.3 Si-0.3 Mn 3 .mu.m TiNi (2 .mu.m)
TiNi.sub.3 (3 .mu.m) 300 700
Example 2
Comparative Fe-13.5 Cr-1.2 Mo-0.4 C-0.3 Si-0.3 Mn 3 .mu.m TiNi (2 .mu.m)
TiNi.sub.3 (3 .mu.m) 350 750
Example 3
Comparative Fe-13.5 Cr-1.2 Mo-0.4 C-0.3 Si-0.3 Mn 0 TiNi (3 .mu.m)
TiNi.sub.3 (4 .mu.m) 350 900
Example 4
Comparative Fe-13.5 Cr-1.2 Mo-0.4 C-0.3 Si-0.3 Mn -- -- --
-- --
Example 5
Comparative Fe-13.5 Cr-1.2 Mo-0.4 C-0.3 Si-0.3 Mn -- -- --
-- --
Example 6
Comparative Fe-13.5 Cr-1.2 Mo-0.4 C-0.3 Si-0.3 Mn 1 .mu.m TiNi (3 .mu.m)
TiNi.sub.3 (4 .mu.m) 350 1100
Example 7
TABLE 2
Laminate
Outermost Thickness of Thickness of
Cooling
Total Layer Outermost Intermediate Intermediate
Annealing Quench Hardening Rate
Thickness (wt %) Layer Layer (wt %) Layer
Treatment Treatment (.degree. C./sec.)
Example 1 0.1 mm Ti 3 .mu.m Ni 8 .mu.m
700.degree. C. .times. 2 min. 1050.degree. C. .times. 2 min. 50
Example 2 0.05 mm Ti 3 .mu.m Ni 5 .mu.m
700.degree. C. .times. 30 sec. 1130.degree. C. .times. 30 sec. 50
Example 3 0.1 mm Ti-0.2 Pd 5 .mu.m Ni 13 .mu.m
750.degree. C. .times. 1 min. 1000.degree. C. .times. 5 min. 1
Example 4 0.08 mm Ti 3 .mu.m Ni 6 .mu.m
800.degree. C. .times. 15 sec. 930.degree. C. .times. 5 min. 20
Example 5 0.1 mm Ti 3 .mu.m Ni 3 .mu.m
800.degree. C. .times. 30 sec. 1000.degree. C. .times. 2 min. 10
Example 6 0.1 mm Ti 3 .mu.m Ni 5 .mu.m
800.degree. C. .times. 1 min. 1050.degree. C. .times. 2 min. 5
Example 7 0.2 mm Ti 10 .mu.m Ni 35 .mu.m --
1050.degree. C. .times. 3 min. 10
Example 8 0.05 mm Ti 4 .mu.m Fe 4 .mu.m
800.degree. C. .times. 30 sec. 950.degree. C. .times. 2 min. 10
Example 9 0.1 mm Ti 4 .mu.m Fe 8 .mu.m
750.degree. C. .times. 1 min. 1050.degree. C. .times. 1 min. 5
Example 10 0.3 mm Ti 10 .mu.m Fe 25 .mu.m
800.degree. C. .times. 2 min. 1150.degree. C. .times. 30 sec. 10
Example 11 0.05 mm Ti 2 .mu.m Ni-20 Cu 5 .mu.m --
1050.degree. C. .times. 2 min. 25
Example 12 0.09 mm Ti-0.2 Pd 4 .mu.m Ni-25 Cu 4 .mu.m --
1000.degree. C. .times. 30 sec. 1
Example 13 0.04 mm Ti 2 .mu.m Ni-15 Cu 8 .mu.m --
1100.degree. C. .times. 5 min. 10
Comparative 0.05 mm Ti 3 .mu.m Ni 5 .mu.m
700.degree. C. .times. 30 sec. 1170.degree. C. .times. 30 sec. 50
Example 1
Comparative 0.05 mm Ti 3 .mu.m Ni 5 .mu.m
700.degree. C. .times. 30 sec. 850.degree. C. .times. 5 min. 50
Example 2
Comparative 0.05 mm Ti 3 .mu.m Ni 5 .mu.m
700.degree. C. .times. 30 sec. 1050.degree. C. .times. 15 sec. 50
Example 3
Comparative 0.05 mm Ti 3 .mu.m Ni 5 .mu.m
700.degree. C. .times. 30 sec. 1050.degree. C. .times. 8 min. 50
Example 4
Comparative 0.05 mm Ti 3 .mu.m Ni 5 .mu.m
650.degree. C. .times. 2 min. -- --
Example 5
Comparative 0.05 mm Ti 3 .mu.m Ni 5 .mu.m
850.degree. C. .times. 5 sec. -- --
Example 6
Comparative 0.05 mm Ti 3 .mu.m Ni 5 .mu.m
700.degree. C. .times. 30 sec. 1130.degree. C. .times. 30 sec. 0.5
Example 7
TABLE 3
Substrate Hardness
Composition of Martensite Stainless Thickness Thickness of
Hard Film Hardness of Hard
Steel (wt %) of TiC TiFe
TiFe.sub.2 Hv Film Hv
Example 14 Fe-13.5 Cr-1.2 Mo-0.4 C-0.3 Si-0.3 Mn 1 .mu.m 2 .mu.m 2
.mu.m 500 800
Example 15 Fe-13.5 Cr-0.6 C-0.2 Mo-0.2 V 1 .mu.m 2 .mu.m 1 .mu.m
500 850
Example 16 Fe-14.0 Cr-0.5 C-0.2 Mo-0.2 V 1 .mu.m 1 .mu.m 1 .mu.m
550 850
Example 17 Fe-14.5 Cr-0.7 C-0.2 Mo-0.2 V 1 .mu.m 5 .mu.m 4 .mu.m
500 800
Example 18 Fe-14 Cr-1.1 C-0.2 Mo-0.2 V 1 .mu.m 6 .mu.m 5 .mu.m
550 800
Example 19 Fe-13 Cr-0.6 C-0.1 Mo-0.1 V 1 .mu.m 1 .mu.m 1 .mu.m
600 900
Example 20 Fe-12.5 Cr-0.5 C-1.5 Mo 1 .mu.m 2 .mu.m 1 .mu.m
550 850
Example 21 Fe-13.5 Cr-0.6 C-0.1 Mo-0.1 V 1 .mu.m 2 .mu.m 2 .mu.m
550 800
Example 22 Fe-13.5 Cr-0.6 C-1.2 Mo-0.3 Si-0.3 Mn 1 .mu.m 3 .mu.m 3
.mu.m 550 850
Example 23 Fe-13.5 Cr-0.6 C-0.2 Mo-0.2 V 2 .mu.m 5 .mu.m 4 .mu.m
450 850
Comparative Fe-13.5 Cr-0.6 C-0.2 Mo-0.2 V 2 .mu.m 5 .mu.m 4 .mu.m
300 850
Example 8
Comparative Fe-13.5 Cr-0.6 C-0.2 Mo-0.2 V 0.5 .mu.m -- -- 350
600
Example 9
Comparative Fe-13.5 Cr-0.6 C-0.2 Mo-0.2 V 0.5 .mu.m 3 .mu.m 3 .mu.m
350 500
Example 10
Comparative Fe-13.5 Cr-0.6 C-0.2 Mo-0.2 V 2 .mu.m 5 .mu.m 3 .mu.m
300 800
Example 11
Comparative Fe-13.5 Cr-0.6 C-0.2 Mo-0.2 V 1 .mu.m 5 .mu.m 4 .mu.m
250 700
Example 12
Comparative Fe-13.5 Cr-0.6 C-0.2 Mo-0.2 V -- -- -- -- --
Example 13
Comparative Fe-13.5 Cr-0.6 C-0.2 Mo-0.2 V -- -- -- -- --
Example 14
Comparative Fe-13.5 Cr-0.6 C-0.2 Mo-0.2 V -- -- -- -- --
Example 15
Comparative Fe-13.5 Cr-0.6 C-0.2 Mo-0.2 V -- -- -- -- --
Example 16
TABLE 4
Laminate
Cooling
Total Outermost Thickness of Annealing Quench
Hardening Rate
Thickness Layer (wt %) Outermost Layer Treatment
Treatment (.degree. C./sec.)
Example 14 0.2 mm Ti 5 .mu.m -- 950.degree.
C. .times. 1 min. 300
Example 15 0.1 mm Ti 4 .mu.m 700.degree. C. .times.
2 min. 950.degree. C. .times. 1 min. 2
Example 16 0.05 mm Ti 3 .mu.m 800.degree. C. .times.
30 sec. 1100.degree. C. .times. 30 sec. 100
Example 17 0.4 mm Ti 10 .mu.m 700.degree. C. .times. 2
min. 950.degree. C. .times. 5 min. 7
Example 18 1 mm Ti 12 .mu.m -- 1050.degree. C.
.times. 2 min. 50
Example 19 0.04 mm Ti 3 .mu.m -- 1100.degree.
C. .times. 30 sec. 20
Example 20 0.2 mm Ti 4 .mu.m -- 1000.degree.
C. .times. 1 min. 10
Example 21 0.08 mm Ti-0.2 Pd 5 .mu.m -- 1000.degree.
C. .times. 30 sec. 50
Example 22 0.1 mm Ti 7 .mu.m -- 1050.degree.
C. .times. 1 min. 300
Example 23 0.2 mm Ti 10 .mu.m -- 1120.degree. C.
.times. 2 min. 2
Comparative 0.1 mm Ti 10 .mu.m -- 1100.degree. C.
.times. 7 min. 10
Example 8
Comparative 0.1 mm Ti 2 .mu.m -- 1050.degree.
C. .times. 15 sec. 10
Example 9
Comparative 0.1 mm Ti 10 .mu.m -- 870.degree. C.
.times. 5 min. 10
Example 10
Comparative 0.1 mm Ti 10 .mu.m -- 1170.degree. C.
.times. 30 sec. 10
Example 11
Comparative 0.1 mm Ti 10 .mu.m -- 1050.degree. C.
.times. 2 min. 0.5
Example 12
Comparative 0.05 mm Ti 3 .mu.m 850.degree. C. .times.
1 min. -- --
Example 13
Comparative 0.1 mm Ti 4 .mu.m 650.degree. C. .times.
2 min. -- --
Example 14
Comparative 0.05 mm Ti 3 .mu.m 700.degree. C. .times.
5 min. -- --
Example 15
Comparative 0.1 mm Ti 4 .mu.m 700.degree. C. .times.
5 sec. -- --
Example 16
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